Field of the Invention
The present invention relates to a lithography apparatus, and a method of manufacturing an article.
Description of the Related Art
There is known an imprint apparatus as a lithography apparatus used for manufacturing semiconductor devices. The imprint apparatus is required to improve the filling property of the imprint material to a pattern formed on a mold from the viewpoints of productivity and accuracy of patterns formed on the substrate. Thus, in Japanese Patent Laid-Open No. 2013-175631, there is proposed a technique of performing an imprint process in a state in which the air in a space between the mold and the substrate (imprint material) is substituted with a gas such as helium or pentafluoropropane.
Furthermore, as disclosed in Japanese Patent No. 4961299, a protection plate (also called a flush plate) is arranged on a substrate holding unit (substrate stage) so that the upper surface of the substrate and the upper surface of the flush plate are flush and so as to surround the periphery of the substrate. The arrangement of such a protection plate in the imprint apparatus allows a mold to maintain a state facing the substrate or the protection plate even if the substrate is moved within the plane to perform an imprint process in each imprint region of the substrate. Hence, it is advantageous in maintaining a constant concentration of a gas in the space between the mold and the substrate.
However, if a gas is supplied to the substrate and the protection plate from a gas supply unit arranged in the upper side of the substrate holding unit, the gas flows to a space below a chuck via a gap between the protection plate and the chuck that holds the substrate. Therefore, it becomes difficult to maintain a constant concentration of a gas in the space between the mold and the substrate without changing the flow rate of the gas supplied from the gas supply unit. Note that the space is provided below the chuck to insert a robot hand for replacing (collecting) the chuck.